1. Technical Field
The present invention relates to an automated headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry method for determining nitrosamine concentration using a polyacrylate fiber.
2. Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
N-nitrosamines (NAs) are a class of organic compounds derived from the reaction of amines (secondary amines) with nitrosating agents (Llop, A., Borrull, F., Pocurull, E., J. Sep. Sci. 2010, 33, 3692-3700.4; Llop, A., Pocurull, E., Borrull, F., J. Chromatogr. A 2010, 1217, 575-581—each incorporated herein by reference in its entirety). NAs are classified as potentially hazardous disinfection by-products (DBPs) produced through a chlorine based disinfection processes of drinking water (Wang, W., Ren. S., Zhang, H., Yu. Y., An. W., Hu. J., Yang. M., Water Res. 2011, 45, 4930-4938—incorporated herein by reference in its entirety). NAs were also present in other anthropogenic source such as polymer waste, plasticizers, rocket fuel (incomplete oxidation of hydrazines), batteries and other industrial products.
As a result, NAs were detected in wide ranges of sample matrices which includes drinking, ground, waste and treated wastewater samples (Anna, V., Rimma, S., Ovadia, L., Jenny, G., Anal. Chim. Acta. 2011, 685, 162-169; Richardson, S. D., Anal. Chem. 2009, 81, 4645-4677—each incorporated herein by reference in its entirety), soils (Pan, X., Zhang, B., Cox, S. B., Anderson, T. A., Cobb, G. P., J. Chromatogr. A 2006, 1107, 2-8—incorporated herein by reference in its entirety), cosmetics (Qiang, M., Hai-Wei, X., Chao, W., Hua, B., Guang-Cheng, X., Ning, S., Li-Yan, X., Jun-Bing, W., Chin. J. Anal. Chem. 2011, 39, 1201-1207; Schothorst, R. C., Somers, H. H. J., Anal. Bioanal. Chem. 2005, 381, 681-685; Flower, C., Carter, S., Earls, A., Fowler, R., Hewlins, S., Lalljie, S., Lefebvre, M., Mavro, J., Small, D., Volpe, N., Int. J. Cosmet. Sci. 2006, 28, 21-33—each incorporated herein by reference in its entirety), biological sample (urine, saliva, blood), tobacco smoke (Ramrez, N., Ozel, M., Lewis, A., Marce, M., Borrull, F., Hamilton, J. Chromatogr. A 2012, 1219, 180-187—incorporated herein by reference in its entirety). Trace amounts of NAs were detected in many food products such as bacon (Ventanas S, Ruiz. J., Talanta 2006, 70, 1017-1023—incorporated herein by reference in its entirety), fish and beer (Sanches, P. J. F., Zanin, K. E., Camarão, E. B., Garcia, R. C., Rios, A., Valcarcel, M., Quimica Nova 2003, 193-196; Mendez, D., Gonzalez, G., Botello, E., Escamilla, E., Alvarado, J. F. J., Food Chem. 2008, 107, 1348-1352—each incorporated herein by reference in its entirety) meat (Campillo, N., Vinas, P., Martnez-Castillo, N., Hernndez-Crdoba, M., J. Chromatogr. 2011, 1218, 1815-1821—incorporated herein by reference in its entirety), and frankfurters and sausages (Oliveira, C. P., Gloria, M. B. A., Barbuor, J., Scalan, R. A., J. Agric. Food Chem. 1995, 43, 967-969—incorporated herein by reference in its entirety).
NAs are receiving special attention due to high toxicity effects and due to the ability to enhance tumors in various animal and human species (Yurchenko, S., Molder, U., Food Chem. 2006, 96, 325-333; Andrade, R., Reyes, F. G. R., Rath, S., Food Chem. 2005, 91, 173-179; Andrade, R., Reyes, F. G. R., Rath, S., Food Chem. 2005, 91, 173-179—each incorporated herein by reference in its entirety). International Agency for Research on Cancer (IARC) and the US Environmental Protection Agency (USEPA) listed NAs as potentially carcinogenic to humans (Kaserzon, S. L., Kennedy, K., Hawker, D. W., Holling, N., Escher, B. I., Booij, K., Mueller, J. F., Chemosphere 2011, 84, 497-503; Boyd, J. M., Hrudey, S. E., Richardson, S. D., Li, X. F., Trends in Analytical Chemistry 2011, 30, 1411-1421—each incorporated herein by reference in its entirety). The USEPA has established the control level (ng/L) of NAs in drinking water (Llop, A., Borrull, F., Pocurull, E., Talanta 2012, 88, 284-289; Fiddler, W., Pensabene, J. W., & Kimoto, W. L., J. Food Sci. 1981, 46, 603-605—each incorporated herein by reference in its entirety).
The most common analytical methods have been used for determination of NAs are (i) colorimetry (Jurado-Sanchez, B., Ballesteros, E., Gallego, M., Talanta 2007, 73, 498-504—incorporated herein by reference in its entirety), (ii) capillary electro-chromatography (CE) (Matyska, M. T., Pesek, J. J., Yang, L., J. Chromatogr. A 2000, 887, 497-503—incorporated herein by reference in its entirety), (iii) micellar electrokinetic capillary chromatography (MECC) (Filho, P. J. S., Rios, A., Valcarcel, M., Caramao, E. B., Water Res. 2003, 37, 3837-3842—incorporated herein by reference in its entirety), (iv) gas chromatography (GC) with different detector such as flame ionization detector (FID) (Jurado-Sanchez, B., Ballesteros, E., Gallego, M., J. Chromatogr A, 2007, 1154, 66-73—incorporated herein by reference in its entirety), nitrogen phosphorous detector (NFD) (Andrade, R., Reyes, F. G. R., Rath, S., Food Chem. 2005, 91, 173-179—incorporated herein by reference in its entirety), thermal energy detector (TED) (Incavo, J. A., Schafer, M. A., Anal. Chim. Acta, 2006, 557, 256-261—incorporated herein by reference in its entirety), nitrogen chemiluminescence detector (NCI)) (Ozel, M. Z., Gogus, F., Yagci, S., Hamilton, J. F., Lewis, A. C., Food Chem. Toxicol. 2010, 48, 3268-3273—incorporated herein by reference in its entirety) and with mass spectrometry detector (MSD) (Anna, V., Rimma, S., Lev, O., Jenny, G., Anal. Chim. Acta. 2011, 685, 162-169—incorporated herein by reference in its entirety). Recently, high-performance liquid chromatography (HPLC) methods with different detectors MSD (Xiong W, Hou H W, Jiang X Y, Tang G L, Hu Q Y. Anal. Chim. Acta, 2010, 674(1): 71-78—incorporated herein by reference in its entirety), ultra violet detector (UVD) (Kodamatani, H., Yamazaki, S., Saito, K., Amponsaa-Karikari, A., Kishikawa, N., Kuroda, N., Tomiyasu, T., Komatsu, Y., J. Chromatogr. A 2009, 1216, 92-98—incorporated herein by reference in its entirety), and fluorescence detectors (FD) (Zhao, Y.-Y., Boyd, J., Hrudey, S. E., Li, X.-F., Environ. Sci. Technol. 2006, 40, 7636-7641—incorporated herein by reference in its entirety) were used for the analysis of NAs. Analysis of NAs by using GC is more sensitive than HPLC methods (Krauss, M., Hollender, J., Anal. Chem. 2008, 80, 834-842; Plumlee, M., Lo´pez-Mesas, M., Heidlberger, A., Ishida, K. P., Reinhard, M., Water Res. 2008, 42, 347-355—incorporated herein by reference in its entirety).
The most common preconcentrating techniques used for NAs in water samples are solid-phase extraction (SPE) with sorbent materials such as carbonaceous Ambersorb-572 and coconut charcoal (Perez, D. M., Alatorre, G. G., Alvarez, E. B., Silva, E. E., Alvarado, J. F. J., Food Chem. 2008, 107, 1348-1352; Planas, C., Palacios, O., Ventura, F., Rivera, J., Caixach, J., Talanta 2008, 76, 906-913—each incorporated herein by reference in its entirety). Alternatively, liquid-liquid extraction (LLE) (Raksit, A., Johri, S., J. AOAC Int. 2001, 84, 1413-1419—incorporated herein by reference in its entirety) was also reported, however, LLE consumes large amounts of organic solvents and is not easy to automate the extraction procedure. Solid-phase microextraction (SPME) (Ventanas, S., Ruiz, J., Talanta 2006, 70, 1017-1023; Grebel, J. E., Young, C. C., Suffet, I. H., J. Chromatogr. A 2006, 1117, 11-18—each incorporated herein by reference in its entirety), which is a solvent-free and more environmentally friendly method is easy to automate using CombiPAL autosampler.
Automated-SPME has more advantages such as a high degree of accuracy and reproducibility compared to the conventional approach. Herein is disclosed the development of a simple automated HS-SPME method using CombiPAL autosampler for the first time for the determination of NAs. Various extraction parameters influencing the performance of HS-SPME such as different type of commercial fibers, extraction time, sample pH, incubation temperature and ionic strength of the aqueous solution were determined using Response Surface Methodology (RSM).